The OSI model and the TCP/IP model

The OSI model and the TCP/IP model
9.1.6 This page provides a comparison of the OSI model and the TCP/IP model.


The OSI and TCP/IP models have many similarities:

• Both have layers.
• Both have application layers, though they include different services.
• Both have comparable transport and network layers.
• Both use packet-switched instead of circuit-switched technology.
• Networking professionals need to know both models.

Here are some differences of the OSI and TCP/IP models:

• TCP/IP combines the OSI application, presentation, and session layers into its application layer.
• TCP/IP combines the OSI data link and physical layers into its network access layer.
• TCP/IP appears simpler because it has fewer layers.
• When the TCP/IP transport layer uses UDP it does not provide reliable delivery of packets. The transport layer in the OSI model always does.

The Internet was developed based on the standards of the TCP/IP protocols. The TCP/IP model gains credibility because of its protocols. The OSI model is not generally used to build networks. The OSI model is used as a guide to help students understand the communication process.

The Interactive Media Activity will help students understand the differences between the TCP/IP and OSI reference models.

The next page examines the basic architecture of the Internet.